Anna Rudawska

Selected aspects of epoxy adhesive compositions curing process

The paper focuses on selected parameters of curing process – temperature and time. The tests aimed at evaluating the impact of short-term thermal recuring on 1050A and 2017A aluminium alloy sheet adhesive joints strength. Joints were formed with two different adhesives, the main component of which was in both cases epoxy resin Epidian 53 and two different cure agents – poliamineamide C (PAC) and triethylenetetraamine (PF) curing agents. Curing conditions – first curing time, recuring time and recuring temperature – were modified for each of the four tests conducted. For the sake of comparative analysis, adhesive joints were subjected to a single-stage cure cycle at ambient temperature. A two-stage cure cycle of both Epidian 53 compositions at 80 °C for 1 and 2 h produces a material of different mechanical properties than the same material which submits a single-stage cure cycle at ambient temperature, as well as at 60 °C for 30 min. Simultaneously, Epidian 53/PF/100:50 composition proves to produce higher joint strength after recuring than Epidian 53/PAC/100:80; the strength of a joint formed with the former composition increases up to 50% when compared with joints subjected to a single-stage cure cycle. Moreover, tests show that recuring of the adhesive joint formed with both compositions at 60 °C for 30 min does not have a considerable influence on either 1050A or 2017A aluminium adhesive joint strength.

TECHNICAL AND ORGANIZATIONAL IMPROVEMENTS OF PACKAGING PRODUCTION PROCESS

Due to customer driven economies, today’s world markets are characterized by high fluctuations in market demand and frequent arrival of new technologies and new products. To stay competitive in such markets manufacturing companies require continuous improvements both in technical and organizational areas of their activity. The paper presents results of the diagnosis provided in the manufacturing area of the company producing cardboard packages and recommendations to make the production process more efficient. Especially, among the proposed technical and organizational recommendations the most important ones are: automation of certain elements of the production process and changes in production plant layout.

Mechanical properties of adhesive bonds reinforced with biological fabric

Abstract The paper deals with the utilization of a biological reinforcement in an area of an adhesive layer. An advantage of the biological reinforcement application is a simplification of following recyclation of adhesive bonds comparing to those with carbon and glass fibre based reinforcements. Biocomposites combining the biological reinforcement with an inorganic adhesive can be used in the area of connecting materials by means of the adhesive bonding technology. This study was focused on the analysis of an adhesive bond strength when the bonds were reinforced with biological fabric such as jute, flax and cotton. It evaluates the quality of the adhesive layer by means of SEM. The aim of this experiment was to describe an influence of the biological reinforcement in the form of fabric on the adhesive bond strength loaded with various loading speeds from 0.5 to 300 mm/min. The experimental part is devoted to the research on the influence of added fabrics of the natural origin on the shear strength of the adhesive bond which is prepared with the polymer adhesive. The experiment results proved a benefit of the reinforcing biological fabric in the layer of the adhesive. The reinforcement of the adhesive bond with the layer of the flax and the cotton showed in the positive way with the increase of the adhesive bond strength up of ca. 50%. The biological reinforcement was not fully wetted with the resin which did not considerably influence the adhesive bond strength.

Milling as a method of surface pre-treatment of steel for adhesive bonding

Abstract The paper analyses the impact of mechanical milling pre-treatment parameters on adhesive joint strength. Comparison of surface roughness of adherends after milling and its effect on adhesive joint strength is analysed in strength tests. The tests were performed on C45 structural steel specimens, which were subjected to machining at different parameters, with two types of milling cutters. Adherends were degreased prior to adhesive joining. Two types of end mills used in tests were NFPaφ20 high-speed steel cutter and R390-020B20-11L indexable milling cutter. The machining was carried out at three cutting speeds: 0.05, 0.15 and 0.30 mm/tooth. Adherends were joined with an adhesive composition of Epidian 57 epoxy resin and Z-1 curing agent.

The effect of primers on adhesive properties and strength of adhesive joints made with polyurethane adhesives

Abstract The paper presents selected aspects of the effect of primers on adhesive properties and strength of aluminium sheet adhesive joints, made using polyurethane adhesives. The strength of adhesive joints was determined based on two cure time variants: 15 and 64 h. It was found that the longer cure time at a humidity of 33% is more desired, as it leads to a substantial increase in strength of the tested adhesive joints. In addition, two variants of surface preparation were applied: degreasing and degreasing followed by the application of a primer (a pro-adhesive agent). It was observed that the primer application prior to the application of an adhesive leads to a significant increase in strength compared to the variant where the adhesive application is preceded only by degreasing. Moreover, the aluminium sheet surface that was subjected to cataphoretic painting and priming exhibits better adhesive properties. It has a higher value of both surface free energy and its dispersion and polar components compared to the surface that was only subjected to degreasing.

Influence of the thickness of joined elements on lap length of aluminium alloy sheet bonded joints

This work features the results of experimental research in determining the limiting length of the bonded single-lap joint of materials of the same thickness, different thicknesses and of hybrid systems of different aluminium alloy sheets. The length of the bonded lap joint is just one of the structural features, critical to the strength of bonded joints, this length depending on the thickness and type of the bonded elements. In the case of single-lap bonded joints there is a limiting lap length exceeding of which should not increase the strength of such joints. This is why the length of a bonded lap joint is critical in terms of strength and application concerns. The length of the lap is not always reflected in practice due to simplification of the analytical relations. What is required is experimental verification of the derived theoretical relations. The tested materials are aluminium alloy sheets, widely used in the machinery, aviation and construction industries.

Effect of active rubber powder on structural two-component epoxy resin and its mechanical properties

Abstract The aim of the research was to investigate a possibility to use active rubber powder (ARP) from a process of tyres recyclation in an area of a filler into a reactoplastics matrix applied in structural adhesive bonds. This study focuses on an analysis of a tensile strength, a shear impact strength and a hardness of the composite mixture itself and further on the interaction with an adhesive bonded material, i.e. it evaluates an influence of different ratio of ARP on the adhesive bond strength. Effects of the cyclic degradation environment combining the decreased temperature −40 °C and the increased temperature 90 °C at the simultaneous acting of the increased moisture up 90% is a part of the research. The tensile strength and the hardness were decreased by adding ARP. The experiment results proved a positive effect of ARP in the area of adhesive bonds exposed to the cyclic degradation at increased and decreased temperatures. Elastic ARP is able to absorb an inner tension in the layer of the adhesive bond.

THE VISUAL METHOD IN QUALITY ASSESSMENT OF SINGLE-LAP ADHESIVE JOINTS

This article presents selected criteria for the quality assessment of single-lap adhesive joints formed on 0.66±0.04 thick hot dip zinc coated sheets with the hot dip zinc coating thickness equal to 18 μm. Three types of epoxy adhesives and three variants of the mass of adhesives were tested (1 g, 2 g and 3 g). The work intended to assess the capacity of the visual method with regard to evaluating joint quality, allowing for the presence and the size of spew fillet, joint dimensions and the effect of spew fillet on adhesive joint strength. The strength of analysed adhesive joints was determined in destructive tests.

Impact of cutting tool geometry on the dynamic load of system in the machining process of nickel Alloy 625

The article is focussed on comparing and determining the impact of the cutting geometry of the cutting tool due to dynamic load on system and microgeometry machined surface. For longitudinal turning nickel alloy Alloy 625 (W. Nr. 2.4856) rounded indexable cutting insert was used (RCMT 10T3M0 – F2) and its equivalent squared indexable cutting insert (SNMG 120412 – MR3) coated with fine-grained PVD (Ti, Al) N + TiN. Experimental testing of nickel Alloy 625 was under predetermined cutting conditions. In the selected depth of the removed material of 0.5 mm and 1.5 mm was measured in the course of machining the size of the individual components of cutting forces.

The Effect of Technological and Structural Factors on the Strength of Polyethylene Adhesive Joints

This paper discusses the issues concerning the strength of PE–HD 500 polyethylene adhesive joints depending on the applied variable structural and technological factors. The variable structural factor was joint geometry: the samples were single-lap joints and butt adhesive joints. As far as the technological factors are concerned, two types of cyanoacrylate adhesives were used (Loctite 401 and Loctite 406), different surface preparation methods were employed (with and without the application of a primer) and different primer-application techniques were used (the primer was applied to one or both adherend surfaces). The primer was selected with respect to the adherend and adhesive types. The samples of the produced adhesive joints were subjected to dimensional analysis followed by destructive testing. The strength tests were performed on the Zwick Roell Z150 testing machine in accordance with the DIN EN 1465 standard. Following the destructive tests, the adhesive joints were examined with respect to failure patterns based on visual valuation and the standard PN-EN ISO 10365. The statistical analysis was performed by the F-Snedecor and T-Student tests, the Cochrane-Cox test as well as relevant statistical models, taking into account the first error type of α = 0.05. The results demonstrate that the adhesive joint strength of elements made of polyethylene is affected by both surface preparation method (including the use of the primer) and the type of adhesive used. It is observed that the strength of adhesive joints increases with increasing the amount of the primer.